There are Chevy bellhousings for them, but they're for the overdrive model. Get that bell, then get an earlier trans with direct top gear, you have to make a spacer ring to go around the input bearing retainer and grind the nose off the input shaft.

These are stout trannies... especially the '70 to '74 versions, or if you want real strength, find an 18-spline input model, they were built for the 426 Hemi.